1. Field of the Invention
The present invention generally relates to angling accessories and particularly to connectors for connecting sections of fishing lines together in a non-permanent manner thereby allowing the changing of fishing line sections without the need for re-tying, or replacing a connector.
More particularly the present invention relates to the connection of sections of fly-fishing line used for the sport of fly-fishing, specifically to the interchangeable use of various sections of fly line of differing densities comprising the terminal section of the fly line proximal to the leader line, as well as connecting leader line to fly line, without the need for knots or loop to loop connections.
2. Description of the Related Art
In the sport of fly-fishing, the lure, or fly, is of light weight, and by itself, is insufficiently heavy to load, or  bend the rod to a sufficient degree to allow it to cast the line, or throw the line by the recoil of the rod as it unloads, or unbends. A fly line is thus used to provide the weight to load, or bend the rod, and the relatively lightweight fly is attached to the fly line by a length of tapered monofilament line (the leader) and is carried along during the cast by the weight of the fly line.
Fly lines are typically composed of a core, which may be a single continuous strand of monofilament, or may consist of a continuous section of tubular braided multifilament material, for example, nylon or Dacron. The core material is selected to perform optimally in the target arena in which the fly line will be used, and comprises the primary strength component of the fly line in resistance to break-age. In turn, the core is coated with a plastic material such as, for example, polyurethane, and polyvinylchloride, in various proprietary formulations and manufacturing processes. This coating of plastic is used to provide a precise distribution of mass along the fly line optimized for various fly-fishing situations.
In an unaltered state, the plastic coatings have a specific gravity of near 1.000. In the manufacture of fly lines, various substances may be included into the molten plastic  coating material to alter the floating or sinking characteristics of a fly line. For increasing the floatation of a fly line, for example, microscopic hollow glass beads are commonly used, and to increase the sinking characteristics of a fly line, solid glass beads or powdered tungsten are commonly used.
In certain fly fishing situations it is advantageous to be able to vary the density of the end or tip section of the fly line that is connected to the leader line. Typically, the original tip section of a floating fly line, usually measuring between ten and twenty-five feet in length, is removed from the body of the fly line, and various substitute sections of fly line of comparable weight and length to the removed section, but consisting of greater densities are connected to the body of the fly line. Using tips of differing densities allows the delivery of the fly to fish that are feeding below the surface. The denser the fly line tip sections the greater depth that the fly reaches.
As the optimal tip density may vary through the course of a fishing day, the capability to rapidly exchange tips of varying density is often advantageous to the fly fisherman. The tips are typically connected to the body of the fly line with an interlocking loop to loop connection. Some commercially  manufactured fly lines have loop to loop connections preconfigured, but the durability of manufactured loop to loop connections has not proven to be as durable as “after market” loops connected to the ends of the fly line and fly line tips and constructed of braided hollow tubular material, such as, for example, monofilament or Kevlar, and add considerable cost to the consumer. These after market connections are typically made by the fly fisher, and consist of forming a loop in the hol-low braided material, or purchasing a preformed braided loop, and passing the cut end of the fly line or tip into the hollow braid. The ends of the braid are secured with an over winding of thread, silicone tubing, or with heat shrink tubing. The braid constricts with elongation, and securely grips the fly line under tension.
Simple, loop to loop connections have an intrinsic disadvantage in that to make an interlocking connection, the entire length of the tip and attached leader line must be drawn through one of the loops. Typically the fly will not fit through the loop and must be removed and reattached. This process is time consuming, as is the construction and placement of after market loop connectors.
Various devices and procedures have been proposed but  none produces an easily removable tip section without time-consuming procedures or having simple interchangeability characteristics.
For example, U.S. Pat. No. 3,722,130 issued Mar. 27, 1973 to Handl teaches the permanent connection of the ends of two lengths of tubular fishing line through the use of a barbed pin inserted into the center of one end of each length of fishing line to be permanently connected.
U.S. Pat. No. 4,117,574 issued Oct. 3, 1978 to Yoshida teaches a device for connecting a leader to the end of a fishing line where the fishing line is passed through the center of one end of the device and then wound around the periphery of the device and locked to the device by passing through at least one bore orientated perpendicular to the longitudinal axis of the device. The leader is then tied to the device by passing through a bore located at the end of the device opposite the end through which the fishing line enters and tied off using a knot.
U.S. Pat. No. 4,604,821 issued Aug. 12, 1986 to Moser teaches a hollow core braided connector into the center of which is permanently attached the end of a fly fishing line and at the other end of which a special three strand twisted leader butt is permanently attached to the  other end of the connector and glued in place U.S. Pat. No. 4,864,767 issued Sep. 12, 1989 to Drosdak teaches a fly fishing line connector comprising an elongated or cigar-shaped body having a loop connector at one end and a jaw means a the other end. The jaw means grips the fly-fishing line end and a locking means permanently locks the jaws closed thereby holding the end of the fly-fishing line. The jaws are locked using locking pins, screws, or an external clamp.
U.S. Pat. No. 5,469,652 issued Nov. 28, 1995 to Drosdak teaches fly fishing leader having a threaded portion located on the butt end which screws into a complimentary threaded connector permanently mountable on the end of a fly fishing line and into which said threaded leader butt may be mounted.
U.S. Patent Application Publication Number 2002/0108294 published Aug. 15, 2002 to Denby teaches a fishing line connector having a loop on one end for attaching the end of one fishing line and a hollow toothed bore in the other end for permanently attaching the end of a second fly-fishing line.